Development and evaluation of a continuous microwave processing system for hydrocarbon removal from solids

Abstract

A continuous conveyor-belt processing concept using microwave heating was developed and evaluated. Four hydrocarbon-contaminated soils were used as model feedstocks, and the degree of organic removal was assessed against the power and energy input to the process. The findings of this study at scale (150kg/h) are in direct agreement with data obtained in batch laboratory scale experiments, and show that microwave heating processes are fundamentally scalable. It is shown that there is a trade-off between the efficiency of organic removal and the power distribution, and applying the power in a single stage was found to be 20-30% more energy efficient but the overall degree of organic removal is limited to 60%. 75% removal was possible using two processing steps in series, but the organic removal is ultimately limited by the amount of power that can be safely and reliably delivered to the process material. The concept presented in this work is feasible when 75% organic removal is sufficient, and could form a viable industrial-scale process based on the findings of this study.

Microwave assisted hydro-distillation of essential oils from fresh ginger root (Zingiber officinaleRoscoe)

“…However, up to this power threshold, it is suggested that the efficiency of the hydro-distillation process of the volatile oils is increased, because the steam distillation/ stripping of the oils in the aqueous phase is more energetic. Heat transfer to the bulk material is also minimized, which has been shown in other similar microwave based oil extraction systems to be a critical factor for the total yield of oil recovered [32].…”

Towards large scale microwave treatment of ores: Part 1 – Basis of design, construction and commissioning

“…This is dependent on the effective integration of the materials handling system with the applicator (Bradshaw et al, 2007;Buttress et al, 2016;Robinson et al, 2010b;Shang et al, 2006). The presentation of the process material in the applicator is critical to matching the impedance of the load to the transmission line so that power transfer can be optimised and the propensity for the system to generate process arcs in certain systems minimised.…”

Microwave pyrolysis of biomass for bio-oil production: Scalable processing concepts

“…Indeed, a lack of data from demonstration plants often prevents successful scale-up because the technical risks have not yet been fully evaluated and mitigated [52].…”

“…They have been evaluated for their electromagnetic compatibility and ability to deliver enough power density to induce pyrolysis without using microwave susceptor additives. Electromagnetic simulations are presented for each concept for heating at 2.45 GHz using a wellestablished procedure [52]. COMSOL Multiphysics® 4.4 has been used to determine the 3D distribution of the electric field (V/m) inside the cavity and within the biomass load, and then to calculate the power density (W/m 3 )…”